Electromagnetic Radiation- Energy that shows wavelike behavior as it travels through space (i.e. radio waves, infrared light, x-rays, etc.).
Electromagnetic Spectrum- The different forms of electromagnetic radiation, seen in the picture below.
When less energy is present, there is a longer wavelength, and when more energy is present, there is a shorter wavelength.
All kinds of electromagnetic radiation move at the speed of 3.00 ´ 108 (m/s) in space, and a slightly slower pace in matter.
Wavelength- (l) The distant between two points on waves that are next to each other.
Frequency- The number of waves that pass a point each second.
Frequency and wavelength are directly related to each other. If frequency of light increases, then wavelength decreases, and vice versa. In the equation c=lv, c= the speed of light (3.00 ´ 108 (m/s)), l = wavelength, and v = frequency. This equation is used to find the frequency or wavelength of a wave.
Example Problems: The first problem’s work is shown as an example for the next two
Find the wavelength of a wave broadcasted by krock (93.7 Mhz).
93.7 Mhz 1,000,000 hz = 93,700,000 hz
1 Mhz
3.00 ´ 108 m/s = 93,700,000hz (l) 3.00´108 m/s = 3.20m
93,700,000
First, you convert Mhz into hz, and then divide the speed of light by the frequency to get the desired answer.
Calculate the frequency of a red light whose frequency is 728nm
Answer 4.12 x 1014 Hz
Calculate the wavelength of a wave whose frequency is 1.9432 ´ 104
Answer .0154m
Photoelectric Effect- When a metal gives off electrons as light is shined on it (demonstrated in the picture)
This is a demonstration of particle/wave duality, showing light with properties of a particle, releasing electrons.
There has to be a minimum frequency for the process to take place. If the frequency is below that minimum, it will not take place.
Quantum- The minimum amount of energy that an atom can gain or lose .
Photon- A particle of electromagnetic radiation that carries one quantum of energy, with no mass.
As indicated in the picture below, When an electron transfers from an energy level of high energy to an energy level of low energy, a photon is emitted.
When an electron transfers from an energy level of lower energy to an energy level of higher energy, the difference of energy between the two levels must be absorbed.
Ground State- The lowest possible energy state of an atom.
Excited State- A state at which the energy in the atom is a larger amount than is
possessed in the ground state.
The equation E = hv is used to find the energy of a wave. E is the energy or quantum (in joules), h is Planck’s constant, (6.626 ´ 10-34) and v is frequency.
Example Problems:
Find the energy of a wave whose frequency is 102.5 Mhz
Determine the frequency of a wave that has 2.782 ´ 10-16 J of energy
Answer: 4.20 ´ 1017 1/s
Determine the energy of a wave whose wavelength is 1.04 pm
Answer: 1.908 ´ 10-13 J
Line-emission Spectrum- Particular frequencies that are given off by a particle when an electric current is passed through it, and is reflected through a prism
Continuous Spectrum- Is a continuous range of frequencies, as seen in the picture, that are given off by visible light
The Quantum Model of the Atom
Vocabulary
Orbital- a three dimensional region around the nucleus that shoes the region in space where an election is most likely to be
Quantum Number- specifies the properties of an atomic orbital and the properties of electrons in an orbital.
- The first quantum numbers indicate the main energy level, shape and orientation
- energy increases as distance from nucleus increases Angular Momentum Quantum Number- indicates shape of orbital
Shape of Orbital
s
p
d
f
Energy levels
1
3
5
7
Magnetic Quantum Number- symbolized by m indicates orientation orbital around nucleus
Important Theories/Principles
HEISENBERG UNCERTAINTY PRINCIPLE- it is impossible to determine simultaneously the position and velocity of an electron or any other particle
QUANTUM THEORY- (Schrödinger) describes mathematically the wave properties of electrons and other particles.
Things to Remember-
· Electrons have dual wave-particle nature
· Quantization of electron energies is a natural outcome of the Schrödinger wave equation
· Each orbital contains 2 electrons
Electron Configurations
Aufbau principle- an electron occupies the lowest energy orbital that can receive it
Pauli Exclusion Principle- no more than to electrons can occupy and orbital and they have to be spinning opposite ways
Hund’s rule- electrons distribute evenly before paring up at a particular energy level.
Orbital Diagrams
1. identify energy level for the atom
2. What types of orbitals can you have?
3. determine which orbitals are actually filled by using your periodic table
4. How many electrons do you have?
5. dram an orbital using boxes as orbitals and arrows as electrons
Remember that the number of boxes correlates with the number of possible orbital combinations in a different energy level (s -1, p-2…)
Examples:
1. Tell which one of A, B, C, or D is correct,
and what element it is
Practice
Do orbital diagrams for
2. Sulfur
3. Iron
Answers:
B is correct, and it is oxygen
Sulfur should
- 3rd energy level
- Fill s and p
- 1s, 2s,2p,3s,3p
- Have 16 electrons
- S’s should have 1 box, P’s should have 3
- Every box should have 2 opposite spinning electrons except the last 2 of 3p
Iron should
- 4th energy level
- Fill s, p, and d
- 1s, 2s, 2p, 3s,3p, 4s, 3d
- Have 26 electrons
- S’s should have 1 box, P’s should have 3, D’s should have 5
- Every box should have 2 opposite spinning electrons except the last 4 of 3d
Noble Gas Configurations
Starting with element, back up to the nearest noble gas
write noble gas in brackets
start with electron configuration after noble gas
-name the energy level appropriate letter
-show how many electrons are in each energy block by writing it in superscript
Chapter 4 – Kathleen, George
The Development of a New Atomic Model
Electromagnetic Radiation- Energy that shows wavelike behavior as it travels through space (i.e. radio waves, infrared light, x-rays, etc.).
Electromagnetic Spectrum- The different forms of electromagnetic radiation, seen in the picture below.
Wavelength- (l) The distant between two points on waves that are next to each other.
Frequency- The number of waves that pass a point each second.
Frequency and wavelength are directly related to each other. If frequency of light increases, then wavelength decreases, and vice versa. In the equation c=lv, c= the speed of light (3.00 ´ 108 (m/s)), l = wavelength, and v = frequency. This equation is used to find the frequency or wavelength of a wave.
Example Problems: The first problem’s work is shown as an example for the next two
- Find the wavelength of a wave broadcasted by krock (93.7 Mhz).
93.7 Mhz 1,000,000 hz = 93,700,000 hz1 Mhz
3.00 ´ 108 m/s = 93,700,000hz (l) 3.00 ´ 108 m/s = 3.20m
93,700,000
First, you convert Mhz into hz, and then divide the speed of light by the frequency to get the desired answer.
- Calculate the frequency of a red light whose frequency is 728nm
Answer 4.12 x 1014 Hz- Calculate the wavelength of a wave whose frequency is 1.9432 ´ 104
Answer .0154mPhotoelectric Effect- When a metal gives off electrons as light is shined on it (demonstrated in the picture)
Quantum- The minimum amount of energy that an atom can gain or lose .
Photon- A particle of electromagnetic radiation that carries one quantum of energy, with no mass.
Ground State- The lowest possible energy state of an atom.
Excited State- A state at which the energy in the atom is a larger amount than is
possessed in the ground state.
The equation E = hv is used to find the energy of a wave. E is the energy or quantum (in joules), h is Planck’s constant, (6.626 ´ 10-34) and v is frequency.
Example Problems:
- Find the energy of a wave whose frequency is 102.5 Mhz
102.5 Mhz 1,000,000 Hz = (1.025 ´ 107)( 6.626 ´ 10-34) = 6.792 ´ 10-26 J1Mhz
- Determine the frequency of a wave that has 2.782 ´ 10-16 J of energy
Answer: 4.20 ´ 1017 1/s- Determine the energy of a wave whose wavelength is 1.04 pm
Answer: 1.908 ´ 10-13 JLine-emission Spectrum- Particular frequencies that are given off by a particle when an electric current is passed through it, and is reflected through a prism
Continuous Spectrum- Is a continuous range of frequencies, as seen in the picture, that are given off by visible light
The Quantum Model of the Atom
Vocabulary
Orbital- a three dimensional region around the nucleus that shoes the region in space where an election is most likely to be
Quantum Number- specifies the properties of an atomic orbital and the properties of electrons in an orbital.
- The first quantum numbers indicate the main energy level, shape and orientation
- energy increases as distance from nucleus increases
Angular Momentum Quantum Number- indicates shape of orbital
Magnetic Quantum Number- symbolized by m indicates orientation orbital around nucleus
Important Theories/Principles
Things to Remember-
· Electrons have dual wave-particle nature
· Quantization of electron energies is a natural outcome of the Schrödinger wave equation
· Each orbital contains 2 electrons
Electron Configurations
Aufbau principle- an electron occupies the lowest energy orbital that can receive it
Pauli Exclusion Principle- no more than to electrons can occupy and orbital and they have to be spinning opposite ways
Hund’s rule- electrons distribute evenly before paring up at a particular energy level.
Orbital Diagrams
1. identify energy level for the atom
2. What types of orbitals can you have?
3. determine which orbitals are actually filled by using your periodic table
4. How many electrons do you have?
5. dram an orbital using boxes as orbitals and arrows as electrons
Examples:
1. Tell which one of A, B, C, or D is correct,
and what element it is
Practice
Do orbital diagrams for
2. Sulfur
3. Iron
Answers:
- B is correct, and it is oxygen
- Sulfur should
- 3rd energy level- Fill s and p
- 1s, 2s,2p,3s,3p
- Have 16 electrons
- S’s should have 1 box, P’s should have 3
- Every box should have 2 opposite spinning electrons except the last 2 of 3p
- Iron should
- 4th energy level- Fill s, p, and d
- 1s, 2s, 2p, 3s,3p, 4s, 3d
- Have 26 electrons
- S’s should have 1 box, P’s should have 3, D’s should have 5
- Every box should have 2 opposite spinning electrons except the last 4 of 3d
Noble Gas Configurations
- Starting with element, back up to the nearest noble gas
- write noble gas in brackets
- start with electron configuration after noble gas
-name the energy level appropriate letter-show how many electrons are in each energy block by writing it in superscript
Example – P
[Ne]
3s2 3p3
You Try:
- Bromine
- Sodium
Answers:
Bromine
[Ar]
4s2 3d10 4p5
Sodium
[Ne]
2s1